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Subtropical Storm Nicole Forecast Discussion


906 
WTNT42 KNHC 080254
TCDAT2

Subtropical Storm Nicole Discussion Number   4
NWS National Hurricane Center Miami FL       AL172022
1000 PM EST Mon Nov 07 2022

Satellite images continue to show the signature of a subtropical
cyclone, with limited deep convective activity near the center and a
large band of convection extending well to the east and southeast.
A subtropical satellite classification from TAFB, along with
observations from NOAA data buoy 41047 indicate little change in
strength, and the current intensity estimate remains at 40 kt.  The
system remains very broad, with the strongest winds well removed
from the center.

Nicole is moving slowly northwestward, or about 310/7 kt, on the
northeastern side of a mid- to upper-level low, and this general
motion is likely to continue into Tuesday morning.  The system
should turn toward the west and west-southwest beginning tomorrow
as an eastward-moving high pressure area builds to its north, and
move over the Florida peninsula on Thursday.  Then, the cyclone is
likely to move around the western periphery of the ridge near
northern Florida and accelerate northeastward ahead of a large
mid-tropospheric trough moving into the east-central United States
around day 4.  Nicole should continue to accelerate northeastward
near the northeastern United States coast around the end of the
forecast period.  The official track forecast is very close to the
simple dynamical model consensus, TVCA, and is also similar to the
previous NHC track.

There is more than the usual amount of uncertainty in the intensity
forecast.  Nicole's sprawling structure and nearby dry
mid-level air suggest that it will take some time for the cyclone to
begin strengthening.  It is expected, however, that the system will
at least begin to acquire an inner core structure within 24 hours
and be near or at hurricane intensity by the time it reaches the
northwest Bahamas and the Florida peninsula.  The official
intensity forecast remains close to the HFIP corrected consensus
guidance and is a little above the GFS and ECMWF global model
wind speed predictions.  Regardless of Nicole's exact intensity,
the storm's large size due to an enhanced pressure gradient north of
the cyclone will likely cause significant wind, storm surge, and
rainfall impacts over a large portion of the northwestern Bahamas,
Florida, and the southeastern coast of the United States during the
next few days.


Key Messages:

1. Hurricane conditions and a dangerous storm surge are expected in
portions of the northwestern Bahamas beginning Tuesday night, where
a Hurricane Warning is in effect.

2.  Hurricane conditions are possible across portions of the coast
of southeast and east-central Florida beginning late Wednesday,
where a Hurricane Watch is in effect.  Tropical storm conditions are
expected in the Tropical Storm Warning areas in Florida and Georgia
beginning early Wednesday.

3. A dangerous storm surge is expected  along much of the east coast
of Florida and portions of coastal Georgia where a storm surge
warning is now in effect. The storm surge will be accompanied by
large and damaging waves.  Residents in the warning area should
listen to advice given by local officials.

4. Do not focus on the exact track of Nicole since it is expected to
be a large storm with hazards extending well to the north of the
center, outside of the forecast cone. These hazards are likely to
affect much of the Florida peninsula and portions of the southeast
U.S.

5. Nicole will produce heavy rainfall by Wednesday night and
Thursday across the Florida Peninsula. Flash and urban flooding will
be possible along with river rises on portions of the St. Johns
River.


FORECAST POSITIONS AND MAX WINDS

INIT  08/0300Z 27.0N  71.1W   40 KT  45 MPH
 12H  08/1200Z 27.4N  72.4W   40 KT  45 MPH
 24H  09/0000Z 27.2N  74.5W   45 KT  50 MPH...TROPICAL CYCLONE
 36H  09/1200Z 26.7N  76.6W   60 KT  70 MPH
 48H  10/0000Z 26.8N  78.8W   65 KT  75 MPH
 60H  10/1200Z 27.5N  81.1W   50 KT  60 MPH...INLAND
 72H  11/0000Z 28.9N  82.6W   40 KT  45 MPH...INLAND
 96H  12/0000Z 33.1N  80.2W   30 KT  35 MPH...INLAND
120H  13/0000Z 41.2N  70.0W   45 KT  50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch




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